Fibonacci Series

Fibonacci series is a series of numbers in which each number is the sum of preceding 2 numbers.Below is fibonacci series with 6 terms.

0  1  1  2  3  5

Code 

#include<stdio.h>

void fib(int);

int main()
{
    int no;

    printf("Enter no of terms ");
    scanf("%d",&no);

    printf("\n%d %d",0,1);

    fib(no);

    return 0;
}

void fib(int no)
{
    static int a=0,b=1,c;

    if(no>2)
    {
        c = a + b;
        a = b;
        b = c;

        printf(" %d",c);

        fib(no-1);
    }
}

Note : A static variable retains its value within function calls.

Code Tracing

When a function invokes,its activation record is pushed on the call stack and when it finishes execution,its activation record is popped off from the call stack.Activation record comprises of many things but I am just showing the things that help understand recursion.Below I trace the fib().